/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.jdbc.datasource.lookup;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.util.Assert;

import javax.sql.DataSource;

/**
 * {@link DataSourceLookup} implementation based on a Spring {@link BeanFactory}.
 *
 * <p>Will lookup Spring managed beans identified by bean name,
 * expecting them to be of type {@code javax.sql.DataSource}.
 *
 * @author Costin Leau
 * @author Juergen Hoeller
 * @see org.springframework.beans.factory.BeanFactory
 * @since 2.0
 */
public class BeanFactoryDataSourceLookup implements DataSourceLookup, BeanFactoryAware {

    private BeanFactory beanFactory;


    /**
     * Create a new instance of the {@link BeanFactoryDataSourceLookup} class.
     * <p>The BeanFactory to access must be set via {@code setBeanFactory}.
     *
     * @see #setBeanFactory
     */
    public BeanFactoryDataSourceLookup() {
    }

    /**
     * Create a new instance of the {@link BeanFactoryDataSourceLookup} class.
     * <p>Use of this constructor is redundant if this object is being created
     * by a Spring IoC container, as the supplied {@link BeanFactory} will be
     * replaced by the {@link BeanFactory} that creates it (c.f. the
     * {@link BeanFactoryAware} contract). So only use this constructor if you
     * are using this class outside the context of a Spring IoC container.
     *
     * @param beanFactory the bean factory to be used to lookup {@link DataSource DataSources}
     */
    public BeanFactoryDataSourceLookup(BeanFactory beanFactory) {
        Assert.notNull(beanFactory, "BeanFactory is required");
        this.beanFactory = beanFactory;
    }


    public void setBeanFactory(BeanFactory beanFactory) {
        this.beanFactory = beanFactory;
    }


    public DataSource getDataSource(String dataSourceName) throws DataSourceLookupFailureException {
        Assert.state(this.beanFactory != null, "BeanFactory is required");
        try {
            return this.beanFactory.getBean(dataSourceName, DataSource.class);
        } catch (BeansException ex) {
            throw new DataSourceLookupFailureException(
                    "Failed to look up DataSource bean with name '" + dataSourceName + "'", ex);
        }
    }

}
